Conventionally, electrostatic capacitance-type pressure sensor devices for measuring vacuum levels in vacuum chambers have been used in manufacturing equipment such as plasma etching equipment and sputtering equipment for manufacturing semiconductors. Depending on the type of the pressure sensor device, the sensor portion may malfunction due to changes in the amount of flexure due to material adhered to the diaphragm face. Because of this, a structure wherein the sensor portion is placed at a high temperature has been proposed in order to prevent such malfunctions (See, for example, Japanese Unexamined Patent Application Publication 2007-155500 (“JP '500”)).
Here, the conventional pressure sensor as set forth in JP '500 is provided with an electrostatic capacitance-type sensor for sensing the pressure of a gas in an external chamber, a heater for heating the sensor to a specific operating temperature, a circuit portion fir generating an output signal indicating the pressure of the gas in the external chamber from a capacitance value sensed by the sensor, and a case for containing the sensor, heater, and circuit portion. Moreover, the case in such a conventional pressure sensor has a sensor containing portion for containing the sensor and the heater, a circuit containing portion for containing the circuit portion, and a thermal propagation preventing portion for partitioning between these containing portions and for preventing the propagation of the heat, produced by the heater, to the circuit containing portion.
However, because the conventional pressure sensor set forth in JP '500 has the sensor containing portion and the circuit containing portion both provided within the same case, a complex thermal insulating structure and heat dissipating structure are needed within the case, increasing the cost. Moreover, the use of a heater for high temperatures in excess of 400° C. makes it necessary to secure an adequate distance between the sensor containing portion and the circuit containing portion within the case, increasing the size of the case concomitantly.
Given this, in order to solve such problems, means have been considered wherein the sensor and the circuit portion are contained in separate cases and separated, connected by a cable, or the like.
However, when the sensor and the circuit portion are connected simply by a cable, the end portion that is connected to the sensor, in particular, may be placed under tension during the connection operation, and there is a risk that it may not be able to withstand high temperatures in excess of 400° C., and a potential that adequate electromagnetic shielding might not have been added. Because of this, there has been the need for new proposals for superior connecting means, in terms of thermal durability, mechanical strength, electromagnetic shielding, and the like, when the sensor and the circuit portion are separated by being enclosed in separate cases.
The present invention is a result of contemplation on this situation, and the object thereof is to increase the thermal durability, the mechanical strength, and the electromagnetic shielding of a structural member that connects between the sensor and the circuit portion in a pressure sensor device that is structured so that the sensor will be put to a high temperature (of for example, about 300 to 450°C.).